A graphene is a two-dimensional nanomaterial formed of carbon atoms. An edge of the two-dimensional material is a topological peculiar part, and physical properties thereof change according to a structure thereof. A graphene has two types of edge structure called zigzag (ZZ) and armchair (AC). It has been theoretically and experimentally reported that due to these differences, a change in physical properties such as electrical characteristics (generation of a band gap in an ultrafine graphene formed of AC edges) or magnetic properties (transition between antiferromagnetism and ferromagnetism in an ultrafine graphene formed of ZZ edges) occurs.
In order to apply such physical properties to an actual device, a graphene processing technique to control an edge structure at an atomic level is necessary, and it is required to realize this technique on a large area substrate of 300 mm or the like for industrial applications. A large area graphene growth technique already exists. However, a metal thin film serving as a substrate is polycrystalline, and therefore a growing graphene also becomes polycrystalline inevitably. This makes processing in a specific direction difficult. Therefore, like other materials, a graphene essentially needs a single crystal/large area growth technique for device application. The inventors have found a single crystal/large area graphene growth method.